An airbag module typically comprises an airbag and an airbag inflator. In the event of a severe vehicle crash, a crash detection system instructs the airbag module to deploy the airbag. The inflator will then provide gas to inflate the airbag. The airbag increases rapidly in volume to cushion the impact of the crash for a vehicle occupant.
The position of the vehicle occupant in relation to the airbag may affect the effectiveness of the airbag as a cushion. For example, if a vehicle occupant is too close to the airbag, full inflation of the airbag may provide less than optimal cushioning. It is therefore desirable to inflate the airbag based on the position of the vehicle occupant.
Systems are known that detect the position of the vehicle occupant and inflate the airbag to an optimal level based on this position. One such system is taught in U.S. Pat. No. 6,129,379 and determines the location of a vehicle occupant based on the rate of inflation of the airbag. At least one sensor tape is located inside of the airbag and is attached to the front side of the airbag. During airbag deployment, these tapes extend with the airbag. A vehicle occupant close to the airbag will interfere with the movement of the front side of the airbag and consequently movement of the sensor tapes. By determining the rate of movement of these tapes, sensors in the airbag module can detect the position of the vehicle occupant and provide this information to a control unit. The control unit system may then adjust the level of inflation of the airbag to accommodate for the vehicle occupant's position.
For such a system, the starting location of the sensor tapes is important to determining the rate of expansion of the airbag and accordingly the position of the vehicle occupant. However, when the airbag is folded using known methods, the airbag may create undesirable folds in the sensor tapes. These folds may disturb the location of these sensor tapes within the airbag and prevent the system from correctly gauging the speed of deployment of the airbag. Consequently, the system may not determine the correct location of the vehicle occupant.
A need therefore exists for an improved airbag folding method that does not disturb the position of the sensor tapes within the airbag.